Image capturing device and image capturing method

ABSTRACT

An image capturing device according to one embodiment includes a camera unit configured to capture images of a surrounding environment and generate image data, a suction-attachment unit configured to support the camera unit and be fixed on a suction-attachment subject surface by a user, a determination unit configured to determine whether or not the image data can be output to a recording unit, and a controller configured to control output of the image data to the recording unit, based on a determination result by the determination unit.

CROSS REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority fromJapanese patent applications No. 2019-036438, filed on Feb. 28, 2019,and No. 2019-058297, filed on Mar. 26, 2019, the disclosures of whichare incorporated herein in its entirety by reference.

BACKGROUND

The present disclosure relates to an image capturing device and an imagecapturing method.

In recent years, small-sized image capturing devices for recording asurrounding environment, such as a wearable camera and an action camera,have been known. In Japanese Unexamined Patent Application PublicationNo. H11-69211, an electronic camera that is, by being attached on awindowpane of a moving vehicle, such as a car and a train, or abuilding, capable of capturing images of a landscape through thewindowpane is disclosed.

SUMMARY

With respect to image capturing devices for recording a surroundingenvironment, prompt start-up of a device and prompt start of recordingof images have been requested. However, since the electronic cameradescribed in Patent Literature 1 starts image-capture only after theuser performs a shutter operation after attaching the electronic cameraon a windowpane, there has been a problem in that recording of imagescaptured by the electronic camera cannot be started promptly.

An image capturing device according to one embodiment includes a cameraunit configured to capture images of a surrounding environment andgenerate image data, a suction-attachment unit configured to support thecamera unit and be fixed on a suction-attachment subject surface by auser, a determination unit configured to determine whether or not theimage data can be output to a recording unit, and a controllerconfigured to control output of the image data to the recording unit,based on a determination result by the determination unit.

An image capturing method according to the one embodiment includes astep of, after a camera unit is fixed on a suction-attachment subjectsurface, capturing images of a surrounding environment with the cameraunit and generating image data, a step of determining whether or not theimage data can be output to a recording unit, and a step of controllingoutput of the image data to the recording unit, based on a determinationresult.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, advantages and features will be moreapparent from the following description of certain embodiments taken inconjunction with the accompanying drawings, in which:

FIG. 1 is a schematic view illustrating a situation in which an imagecapturing device according to a first embodiment is installed in atrain;

FIG. 2 is a schematic cross-sectional view illustrating a configurationof the image capturing device according to the first embodiment;

FIG. 3 is a schematic cross-sectional view illustrating the imagecapturing device suction-attached on a suction-attachment subjectsurface;

FIG. 4 is a schematic cross-sectional view illustrating the imagecapturing device tilted from a state in FIG. 3;

FIG. 5 is a block diagram illustrating a configuration of the imagecapturing device according to the first embodiment;

FIG. 6 is a flow diagram illustrating a control flow of the imagecapturing device according to the first embodiment;

FIG. 7 is a block diagram illustrating a configuration of an imagecapturing device according to a second embodiment; and

FIG. 8 is a flow diagram illustrating a control flow of the imagecapturing device according to the second embodiment.

DETAILED DESCRIPTION

Hereinafter, specific embodiments will be described in detail withreference to the drawings. In the respective drawings, the same orcorresponding components will be denoted by the same reference numerals,and, for convenience of description, overlapping descriptions thereofwill be omitted as needed.

First Embodiment

FIGS. 1 and 2 are a schematic view illustrating a situation in which animage capturing device 1 according to a first embodiment is installed ina train T and a schematic cross-sectional view illustrating a detailedconfiguration of the image capturing device 1, respectively. The imagecapturing device 1 according to the present embodiment is a deviceconfigured to be suction-attached on a windowpane of a vehicle or awindowpane of a house and capture images of a surrounding environmentthrough the windowpane on which the image capturing device 1 issuction-attached. In the example in FIG. 1, using a windowpane of thetrain T as a suction-attachment subject surface 9, the image capturingdevice 1 is suction-attached on the suction-attachment subject surface9.

As illustrated in FIGS. 1 and 2, the image capturing device 1 includes acamera unit 11, a suction-attachment unit 12, and a control unit 13. Thecamera unit 11 captures an image of a surrounding environment outsidethe train T through the suction-attachment subject surface 9 andgenerates image data. Note that the field of view of the camera unit 11has, for example, an angular spread with an included angle ofapproximately 130 degrees as illustrated by the alternate long and shortdash lines. The suction-attachment unit 12 supports the camera unit 11and is fixed by a user. The suction-attachment unit 12 is fixed on thesuction-attachment subject surface 9 by being pressed in thesuction-attaching direction from the outside. The control unit 13 startsoutput of image data to a recording unit when a load applied to theimage capturing device 1 from the outside satisfies a predeterminedstart condition. Such a configuration enables image capturing andrecording by the image capturing device 1 to be started from a point oftime at which the image capturing device 1 is suction-attached on thesuction-attachment subject surface 9. Therefore, it is possible tocapture images of and record a surrounding environment promptly.

As illustrated in FIG. 2, the camera unit 11 includes a lens 111 and isjoined to the control unit 13. The suction-attachment unit 12 includes asuction cup 121, a transparent plate 122, a support portion 123, and ahousing portion 124. Note that the alternate long and short dash lineindicates an image capturing direction in which the camera unit 11 cancapture an image. Note also that the camera unit 11 and the control unit13, although formed in one body in FIG. 2, may be separate entities.

The housing portion 124 is a container-shaped member that has a hollowspace in the interior thereof. The front end of the housing portion 124is formed into a spherical shape. At the time of use, the camera unit 11is housed inside the housing portion 124. The lens 111 of the cameraunit 11 is arranged on the front end side inside the housing portion124.

The support portion 123 is a cylindrically shaped member that has athrough-hole in the axial direction, and, on a portion of thethrough-hole, the same spherical space as the front end of the housingportion 124 is formed. The housing portion 124 being housed in thespherical space formed on the support portion 123 causes the supportportion 123 and the housing portion 124 to be fitted to each other in afreely rotatable manner.

The suction cup 121 is a suction cup that is formed of flexible resinmaterial or the like in one body into a dome shape or a skirt shape. Anouter periphery of the suction cup 121 suction-attaches on thesuction-attachment subject surface 9 by being pressed onto thesuction-attachment subject surface 9. In addition, an opening portion isformed on a portion on the projection side of the suction cup 121, andthe transparent plate 122 is fitted into the opening portion. Theportion on the projection side of the suction cup 121 and thetransparent plate 122 are joined to the support portion 123.

Of the suction-attachment unit 12, the transparent plate 122 and atleast a portion on the image capturing direction side of the housingportion 124 are formed of a transparent material, such as acrylic andglass. In addition, at least a portion on the image capturing directionside of the support portion 123 is opened. Therefore, thesuction-attachment unit 12 supports the camera unit 11 without blockingthe optical path of the camera unit 11. Note that the suction cup 121and the support portion 123 preferably have light shielding property ofcutting off light from the surroundings. The suction cup 121 and thesupport portion 123 having light shielding property enables light fromdirections other than the image capturing direction to be prevented fromfiltering in and the image quality of the camera unit 11 to be improved.

FIG. 3 is a schematic cross-sectional view illustrating the imagecapturing device 1 fixed on the suction-attachment subject surface 9. Asillustrated in FIG. 3, the suction-attachment unit 12, by being pressedin the suction-attaching direction from the outside, has a decompressedsealed space 91 formed between the suction-attachment unit 12 and thesuction-attachment subject surface 9 and is thereby fixed on thesuction-attachment subject surface 9. The sealed space 91 is a spacethat is surrounded and sealed by the suction cup 121, the transparentplate 122, and the suction-attachment subject surface 9. In addition,the suction-attaching direction is a direction that is, as illustratedby the left direction arrow in FIG. 3, directed from thesuction-attachment unit 12 toward the suction-attachment subject surface9.

The suction-attachment unit 12 being pulled in the detaching directionfrom the outside causes the suction cup 121 and the suction-attachmentsubject surface 9 to be pulled away from each other and thesuction-attachment unit 12 to be detached from the suction-attachmentsubject surface 9. The detaching direction is a direction that is, asillustrated by the right direction arrow in FIG. 3, directed from thesuction-attachment subject surface 9 toward the suction-attachment unit12.

FIG. 4 is a schematic cross-sectional view illustrating the imagecapturing device 1 fixed on the suction-attachment subject surface 9when the camera unit 11 is tilted. As illustrated in FIG. 4, rotatingthe housing portion 124 along the inner wall of the support portion 123enables the image capturing direction of the camera unit 11 to berotated. When the inner wall of the support portion 123 and the frontend of the housing portion 124 are formed into spherical shapes, thecamera unit 11 can be rotated in the vertical direction and thehorizontal direction.

Note that, although, in the examples in FIGS. 2 to 4, the descriptionwas made assuming that the suction-attachment unit 12 includes thetransparent plate 122, the suction-attachment unit 12 does not have toinclude the transparent plate 122. In this case, a space surrounded andsealed by the suction cup 121, the support portion 123, the housingportion 124, and the suction-attachment subject surface 9 beingdecompressed causes the suction-attachment unit 12 to besuction-attached on the suction-attachment subject surface 9. Inaddition, in this case, applying lubricant, such as grease, between thesupport portion 123 and the housing portion 124 enables the housingportion 124 to be rotated without impairing the airtightness of thesealed space.

In addition, although, in the examples in FIGS. 2 to 4, the descriptionwas made assuming that the suction-attachment unit 12 includes thesuction cup 121, another type of member can be used in place of thesuction cup 121 as long as the member can be fixed on thesuction-attachment subject surface 9 by being pressed in thesuction-attaching direction from the outside. For example, in place ofthe suction cup 121, rubber tape or adhesive tape having adhesion can beused.

Next, a control system of the image capturing device 1 will bedescribed. FIG. 5 is a block diagram illustrating a system configurationof the image capturing device 1. As illustrated in FIG. 5, the controlsystem of the image capturing device 1 is mainly constituted by thecamera unit 11 and the control unit 13. In addition, the image capturingdevice 1 according to the present embodiment further includes arecording unit 140 in addition to the camera unit 11 and the controlunit 13.

The camera unit 11 mainly includes the lens 111, an imaging element 112,and an analog front end (AFE) 113. The control unit 13 mainly includes acontroller 131, an image input interface (IF) 132, a work memory 133, asystem memory 134, an image processing unit 135, an image output unit136, a brightness determination unit 137, a bus line 138, and asuction-attachment detection unit 139.

The suction-attachment detection unit 139 is an element configured todetect a load in the suction-attaching direction applied from theoutside. The suction-attachment detection unit 139 is, for example, aload sensor of a piezoelectric type or a strain gauge type and is placedat a location, such as a joining portion between the camera unit 11 andthe control unit 13, that expands and contracts in response to a loadfrom the outside. In this case, the suction-attachment detection unit139 is capable of detecting a compression load applied from the outsideas a load in the suction-attaching direction. Note that thesuction-attachment detection unit 139 may further include a tilt sensoror a gyro sensor configured to detect a direction of the load sensor andacquire an angle between the direction of the load sensor and thesuction-attaching direction. In this case, the suction-attachmentdetection unit 139 detects a length of a compression load vector that isprojected onto the suction-attaching direction as a load in thesuction-attaching direction. In such a configuration, even when thecamera unit 11 and the control unit 13 are tilted, it is possible todetect a load in the suction-attaching direction accurately.

When a load in the suction-attaching direction is applied from theoutside, the suction-attachment detection unit 139 outputs a voltagesignal corresponding to the load in the suction-attaching direction tothe controller 131. Specifically, the suction-attachment detection unit139, when detecting a detectable load, outputs a voltage signal having avoltage value proportional to the magnitude of the detected load to thecontroller 131. While detecting a load, the suction-attachment detectionunit 139 continuously outputs a voltage signal. The controller 131 iscapable of, by converting a voltage signal from the suction-attachmentdetection unit 139 into a voltage value, obtaining the magnitude of aload applied in the suction-attaching direction from the outside. Inaddition, the controller 131 is capable of obtaining applicationduration of a load applied in the suction-attaching direction from theoutside from a period of time during which a voltage signal iscontinuously output. The application duration of a load is length of aperiod of time during which the suction-attachment detection unit 139has continuously detected the load.

In the present embodiment, the suction-attachment detection unit 139further detects a load in the detaching direction applied from theoutside. The suction-attachment detection unit 139 is, for example, aload sensor of a piezoelectric type or a strain gauge type and is placedat a location, such as a joining portion between the camera unit 11 andthe control unit 13, that expands and contracts in response to a loadfrom the outside. In this case, the suction-attachment detection unit139 is capable of detecting a tensile load applied from the outside as aload in the detaching direction. Note that the suction-attachmentdetection unit 139 may further include a tilt sensor or a gyro sensorconfigured to detect a direction of the load sensor and acquire an anglebetween the direction of the load sensor and the detaching direction. Inthis case, the suction-attachment detection unit 139 detects a length ofa tensile load vector that is projected onto the detaching direction asa load in the detaching direction. In such a configuration, even whenthe camera unit 11 and the control unit 13 are tilted, it is possible todetect a load in the detaching direction accurately.

When a load in the detaching direction is applied from the outside, thesuction-attachment detection unit 139 outputs a voltage signalcorresponding to the load in the detaching direction to the controller131. Specifically, the suction-attachment detection unit 139, whendetecting a detectable load, outputs a voltage signal having a voltagevalue proportional to the magnitude of the detected load to thecontroller 131. While detecting a load, the suction-attachment detectionunit 139 continuously outputs a voltage signal. The controller 131 iscapable of, by converting a voltage signal from the suction-attachmentdetection unit 139 into a voltage value, obtaining the magnitude of aload applied in the detaching direction from the outside. In addition,the controller 131 is capable of obtaining application duration of aload applied in the detaching direction from the outside from a periodof time during which a voltage signal is continuously output.

The controller 131 is, for example, a CPU and controls respectivecomponents constituting the camera unit 11 and the control unit 13directly or indirectly. For example, the controller 131 determineswhether or not the magnitude and application duration of a load appliedin the suction-attaching direction from the outside satisfy apredetermined start condition. When determining that the start conditionis satisfied, the controller 131 controls the camera unit 11 to startgeneration of image data.

The lens 111 of the camera unit 11 is an optical element configured toguide incident subject luminous flux to the imaging element 112. Thelens 111 may be constituted by a group of a plurality of optical lenses.The imaging element 112 is, for example, a CMOS image sensor. Theimaging element 112 adjusts charge accumulation time by means of anelectronic shutter in accordance with an exposure time per framespecified by the controller 131, performs photoelectric conversion, andoutputs pixel signals. The imaging element 112 hands over the pixelsignals to the AFE 113. The AFE 113 performs level adjustment on thepixel signals according to amplification gain instructed by thecontroller 131, analog/digital (A/D) converts the adjusted pixel signalsinto digital data, and transmits the digital data to the control unit 13as image data. Note that the camera unit 11 may include a mechanicalshutter and an iris diaphragm. When the camera unit 11 includes amechanical shutter and an iris diaphragm, the controller 131 can, by usethereof, adjust the amount of light incident on the imaging element 112.

The image input IF 132 bears the function of an image data acquisitionunit configured to successively acquire image data captured by thecamera unit 11, that is, acquires image data from the camera unit 11connected to the control unit 13 and hands over the acquired image datato the bus line 138.

The work memory 133 is constituted by, for example, a volatile highspeed memory. The work memory 133 accepts image data from the AFE 113via the image input IF 132 and stores the accepted image data as oneframe of image data. The work memory 133 hands over image data to theimage processing unit 135 in units of frame. In addition, the workmemory 133 is also appropriately used as a temporary storage area whenthe image processing unit 135 is in the process of performing imageprocessing.

The image processing unit 135 performs various types of image processingon image data accepted from the work memory 133 and generates frameimages conforming to a predetermined format. For example, when videoimage data in the MPEG file format are generated, white balanceprocessing, gamma processing, and the like are performed on respectiveframes of image data and, subsequently, compression processing withineach frame of image data and compression processing among adjacentframes of image data are performed. The image processing unit 135successively generates frame images on which the respective processingis performed and hands over the generated frame images to the bus line138.

The image output unit 136, when instructed by the controller 131,outputs image data accepted from the work memory 133 to the recordingunit 140. Alternatively, the image output unit 136 may convert frameimages accepted from the image processing unit 135 into image data againand output the image data to the recording unit 140.

The recording unit 140 is a device capable of recording output imagedata, and a nonvolatile memory, such as a flash memory, can be used asthe recording unit 140. Note that, although, in FIG. 5, an example inwhich the recording unit 140 is included in the image capturing device 1is illustrated, the recording unit 140 may be included in a terminalexternal to the image capturing device 1. In this case, the image outputunit 136 outputs image data to the external recording unit 140 by meansof wireless or wired communication via, for example, a communication IF(not illustrated) included in the control unit 13.

The brightness determination unit 137 (also referred to as a“determination unit”) determines brightness of frame images acceptedfrom the image processing unit 135. For example, the brightnessdetermination unit 137 extracts a value of the luminance signal Y fromYCbCr information of each pixel included in a frame image and calculatesan average value of the luminance values of the respective pixels asbrightness of the frame image. The brightness determination unit 137outputs calculated brightness of frame images to the controller 131.Note that the brightness determination unit 137 may arbitrarily extractsome pixels included in a frame image and calculate an average value ofluminance values of the pixels as brightness of the frame image. Inaddition, the brightness determination unit 137 may acquire RGBinformation of each pixel in place of YCbCr information and, using agenerally known conversion formula, convert the RGB information intoluminance information. On this occasion, the brightness determinationunit 137 may approximately calculate a luminance value of each pixel byconverting only the G value of the RGB information. In addition, thebrightness determination unit 137 may convert YCbCr information of eachpixel included in a frame image into luminosity information andcalculate an average value of luminosity values of the respective pixelsas brightness of the frame image. Further, the brightness determinationunit 137 may extract a value of the luminance signal Y from YCbCrinformation of each pixel included in image data accepted from the workmemory 133 and calculate brightness of frame images.

The system memory 134 is constituted by a nonvolatile recording medium,such as a solid-state drive (SSD). The system memory 134 records andretains constants, variables, set values, control programs, and the likethat are necessary at the time of operation of the image capturingdevice 1. Control performed by the controller 131 is achieved by controlprograms and the like read from the system memory 134.

Next, a control flow of the image capturing device 1 will be described.FIG. 6 is a flow diagram illustrating the control flow of the imagecapturing device 1. The flow is started at a point of time at which thecontrol unit 13 becomes ready to operate. The point of time at which thecontrol unit 13 becomes ready to operate is, for example, a point oftime at which the user turns on the power supply of the image capturingdevice 1.

First, in step S10, the suction-attachment detection unit 139 detects aload in the suction-attaching direction applied from the outside. Thesuction-attachment detection unit 139 outputs a voltage signalcorresponding to the magnitude of the load in the suction-attachingdirection applied from the outside to the controller 131. When unable todetect a load in the suction-attaching direction applied from theoutside, the suction-attachment detection unit 139 does not have tooutput a voltage signal to the controller 131. The controller 131converts an accepted voltage signal into information on a voltage valueand application duration and thereby acquires information on themagnitude of the load in the suction-attaching direction applied fromthe outside and application duration of the load. Subsequently, the flowproceeds to step S20,

When the flow proceeds to step S20, the controller 131 determineswhether or not a relationship between the magnitude and applicationduration of the load in the suction-attaching direction detected by thesuction-attachment detection unit 139 satisfies a predetermined startcondition. The start condition is a condition that is satisfied when aload required for the suction-attachment unit 12 to suction-attach onthe suction-attachment subject surface 9 is applied from the outside.

For example, it can be defined that, when a load the magnitude of whichis equal to or greater than a preset suction-attaching load value (forexample, 10 G) is applied in the suction-attaching direction for apreset suction-attaching duration (for example, 1 second), the startcondition is satisfied. Alternatively, it can be defined that, when aload is applied in the suction-attaching direction in such a way thatthe product of the magnitude of the load and application duration of theload becomes equal to or greater than a preset suction-attaching impulsevalue (for example, 100 N□s), the start condition is satisfied. In theexamples described above, specific numerical values of thesuction-attaching load value, the suction-attaching duration, and thesuction-attaching impulse value are determined depending on thestructure, physical properties, and the like of the suction-attachmentunit 12. For example, the numerical values can be determined throughphysical simulation or preliminary experiment.

When a relationship between the magnitude and application duration ofthe load in the suction-attaching direction satisfies theabove-described start condition (Yes in step S20), the flow proceeds tostep S30 and generation and the like of image data are started. On theother hand, when the relationship between the magnitude and applicationduration of the load in the suction-attaching direction does not satisfythe above-described start condition (No in step S20), the flow returnsto step S10 and the step is repeated. In such a configuration, since nosooner does the image capturing device 1 suction-attach on thesuction-attachment subject surface 9 than the generation and the like ofimage data are started, it is possible to start output of image datapromptly.

When the flow proceeds to step S30, the controller 131 makes the cameraunit 11 operate and capture images of the surrounding environment andgenerate image data. In addition, the controller 131 makes the imageprocessing unit 135 perform various types of image processing on thegenerated image data and generate frame images. Subsequently, the flowproceeds to step S40.

When the flow proceeds to step S40, the controller 131 determineswhether or not the brightness of frame images that the brightnessdetermination unit 137 determined satisfies a predetermined brightnesscriterion. The brightness criterion is a criterion that is satisfiedwhen the camera unit 11 receives light from the surrounding environment.In other words, the brightness criterion is not satisfied when thecamera unit 11 does not receive light from the surrounding environmentand thus cannot generate normal image data.

For example, when an average of luminance values of pixels included in aframe image is equal to or greater than a preset luminance criterionvalue (for example, 10), it is determined that the predeterminedbrightness criterion is satisfied. In the example, a specific numericalvalue of the luminance criterion value is determined depending onimage-capturing precision and the like of the camera unit 11. Forexample, a luminance value of a frame image when darkness is capturedcan be determined as the luminance criterion value.

When the brightness of the frame images satisfies the above-describedbrightness criterion (Yes in step S40), the flow proceeds to step S50.On the other hand, when the brightness of the frame images does notsatisfy the above-described brightness criterion (No in step S40), theflow is terminated without outputting image data to the recording unit140. In such a configuration, when no normal image data can be generatedbecause the optical path of the camera unit 11 is cut off, such as whenthe image capturing device 1 is mistakenly suction-attached to anon-transparent object, it is possible to prevent output of image datafrom being started.

When the flow proceeds to step S50, the controller 131 controls theimage output unit 136 to start output of image data to the recordingunit 140. Starting output of image data includes outputting image datato the outside of the image capturing device 1 by means of wireless orwired communication via a communication IF (not illustrated).Subsequently, the flow proceeds to step S60.

When the flow proceeds to step S60, the suction-attachment detectionunit 139 detects a load in the detaching direction applied from theoutside. The suction-attachment detection unit 139 outputs a voltagesignal corresponding to the magnitude of the load in the detachingdirection applied from the outside to the controller 131. When unable todetect a load in the detaching direction applied from the outside, thesuction-attachment detection unit 139 does not have to output a voltagesignal to the controller 131. The controller 131 converts the acceptedvoltage signal into information on a voltage value and applicationduration and thereby acquires information on the magnitude of the loadin the detaching direction applied from the outside and applicationduration of the load. Subsequently, the flow proceeds to step S70.

When the flow proceeds to step S70, the controller 131 determineswhether or not a relationship between the magnitude and applicationduration of the load in the detaching direction detected by thesuction-attachment detection unit 139 satisfies a predetermined stopcondition. The stop condition is a condition that is satisfied when aload required for the suction-attachment unit 12 to be detached from thesuction-attachment subject surface 9 is applied from the outside.

For example, it can be defined that, when a load the magnitude of whichis equal to or greater than a preset detaching load value (for example,10 G) is applied in the detaching direction for a preset detachingduration (for example, 1 second), the stop condition is satisfied.Alternatively, it can be defined that, when a load is applied in thedetaching direction in such a way that the product of the magnitude andapplication duration of the load becomes equal to or greater than apreset detaching impulse value (for example, 100 N□s), the stopcondition is satisfied. In the examples described above, specificnumerical values of the detaching load value, the detaching duration,and the detaching impulse value are determined with the structure,physical properties, and the like of the suction-attachment unit 12taken into consideration. For example, the numerical values can bedetermined through physical simulation or preliminary experiment.

When a relationship between the magnitude of the load in the detachingdirection and application duration of the load satisfies theabove-described stop condition (Yes in step S70), output of image datato the recording unit 140 is stopped and the flow is terminated. On theother hand, when the relationship between the magnitude and applicationduration of the load in the detaching direction does not satisfy theabove-described stop condition (No in step S70), the flow returns tostep S10 and the step and subsequent steps are repeated. In such aconfiguration, since no sooner is the image capturing device 1 detachedfrom the suction-attachment subject surface 9 than the generation andthe like of image data are stopped, it is possible to stop output ofimage data promptly.

By repeating steps S10 to S70, which have been described thus far, theimage capturing device 1 is capable of recording the surroundingenvironment promptly. It should be noted that the present disclosure isnot limited to the above-described embodiment and can be appropriatelymodified as long as the modification does not deviate from the scope ofthe present embodiment.

For example, although, in the above-described embodiment, in order todescribe an image capturing device according to the present disclosure,the description was made using as an example a device configured tocapture an image of a surrounding environment on the outside through asuction-attachment subject surface, the image capturing device accordingto the present disclosure is not limited to the above-described example.That is, the image capturing device according to the present disclosuremay be a device configured to capture images of a surroundingenvironment in the opposite direction to the suction-attaching directionor the vertical direction. In such a device, having a configurationequivalent to those of the camera unit 11 and the control unit 13described above and repeating processing in steps S10 to S70 enable theimage capturing device to record a surrounding environment promptly.

In addition, in the above-described embodiment, a portion of processingin steps S10 to S70 may be appropriately omitted or the order ofexecution of the processing in steps S10 to S70 may be rearranged withinan extent not impairing advantageous effects of the present disclosure.For example, when, after it is once determined that brightness of aframe image satisfies a brightness criterion in step S40 (Yes in stepS40), the processing from step S30 onward is repeated again, theprocessing in step S40 in the second or later round may be appropriatelyomitted. Omitting the processing in step S40 in the second or laterround enables the control flow to be simplified.

In addition, although, in the above-described embodiment, a case wherethe controller of the image capturing device makes the camera unitoperate when determining that the start condition is satisfied wasdescribed, the camera unit may be configured to constantly operate.Alternatively, the camera unit may start operation by a start-upoperation by the user.

Note that, in the above-described embodiment, it is preferable toinclude a condition requiring application duration of a load to be equalto or longer than a preset suction-attaching duration in the startcondition. Such a configuration enables the image capturing device to beprevented from malfunctioning when a load in the suction-attachingdirection is instantaneously applied, such as when the image capturingdevice hits some object.

In addition, in the above-described embodiment, it is preferable toinclude a condition requiring application duration of a load to be equalto or longer than a preset detaching duration in the stop condition.Such a configuration enables the image capturing device to be preventedfrom malfunctioning when a load in the detaching direction isinstantaneously applied, such as when the image capturing device hitssome object.

Second Embodiment

Next, an image capturing device according to a second embodiment will bedescribed. FIG. 7 is a block diagram illustrating a configuration of theimage capturing device according to the second embodiment. An imagecapturing device 2 according to the second embodiment differs from theimage capturing device 1 according to the first embodiment in aconfiguration of a control unit 23 in the block diagram illustrated inFIG. 7. Since the configurations of the other components are similar tothe device configuration described in the first embodiment (see FIGS. 1to 4), descriptions of overlapping explanations will be omitted.

As illustrated in FIG. 7, a control system of the image capturing device2 is mainly constituted by a camera unit 11 and the control unit 23. Inaddition, the image capturing device 2 according to the presentembodiment further includes a recording unit 242 in addition to thecamera unit 11 and the control unit 23.

The camera unit 11 mainly includes a lens 111, an imaging element 112,and an analog front end (AFE) 113. The control unit 23 mainly includes acontroller 231, an image input interface (IF) 232, a work memory 233, asystem memory 234, an image processing unit 235, a movementdetermination unit 236, a suction-attachment determination unit 237, asuction-attachment detection unit 238, an image output unit 239, abrightness determination unit 240, and a bus line 241. Note that,herein, the movement determination unit 236, the suction-attachmentdetermination unit 237, and the brightness determination unit 240 aresometimes collectively referred to as “determination units”. Inaddition, the movement determination unit 236, the suction-attachmentdetermination unit 237, and the brightness determination unit 240 may berepresented by one functional block (“determination unit”).

The suction-attachment detection unit 238 detects a physical quantityrepresenting a relationship between a suction-attachment unit 12 and asuction-attachment subject surface 9 (see FIGS. 1 and 3). Examples ofthe physical quantity representing a relationship between thesuction-attachment unit 12 and the suction-attachment subject surface 9includes the magnitude of stress applied between the suction-attachmentunit 12 and the suction-attachment subject surface 9 and pressure in aspace between the suction-attachment unit 12 and the suction-attachmentsubject surface 9 (a sealed space 91). The suction-attachment detectionunit 238 outputs a voltage signal corresponding to the detected physicalquantity to the bus line 241.

Note that the suction-attachment detection unit 238 may be disposedoutside the control unit 23. In that case, the suction-attachmentdetection unit 238 outputs a voltage signal to a detection signal IF(not illustrated) disposed in the control unit 23. The detection signalIF (not illustrated) successively acquires the voltage signal from thesuction-attachment detection unit 238 and hands over the acquiredvoltage signal to the bus line 241.

In the present embodiment, an example in which the suction-attachmentdetection unit 238 detects the magnitude of stress applied between thesuction-attachment unit 12 and the suction-attachment subject surface 9will be described. The stress applied between the suction-attachmentunit 12 and the suction-attachment subject surface 9 is a load in thesuction-attaching direction applied to the image capturing device 2 fromthe outside. On this occasion, the suction-attachment detection unit 238is, for example, a load sensor of a piezoelectric type or a strain gaugetype and is arranged at a location, such as a joining portion betweenthe camera unit 11 and the control unit 23, that expands and contractsin response to a load from the outside. In this case, thesuction-attachment detection unit 238 is capable of detecting acompression load applied from the outside as a load in thesuction-attaching direction. Note that the suction-attachment detectionunit 238 may further include a tilt sensor configured to detect adirection of the load sensor and acquire an angle between the directionof the load sensor and the suction-attaching direction. In this case,the suction-attachment detection unit 238 detects a length of acompression load vector that is projected onto the suction-attachingdirection as a load in the suction-attaching direction. In such aconfiguration, even when the camera unit 11 and the control unit 23 aretilted, it is possible to detect a load in the suction-attachingdirection accurately.

When a load in the suction-attaching direction is applied from theoutside, the suction-attachment detection unit 238 outputs a voltagesignal corresponding to the load in the suction-attaching direction tobus line 241. Specifically, the suction-attachment detection unit 238,when detecting a detectable load, outputs a voltage signal having avoltage value proportional to the magnitude of the detected load to thecontroller 231. While detecting a load, the suction-attachment detectionunit 238 continuously outputs a voltage signal. The controller 231 iscapable of, by converting a voltage signal from the suction-attachmentdetection unit 238 into a voltage value, obtaining the magnitude of aload applied in the suction-attaching direction from the outside. Inaddition, the controller 231 is capable of obtaining applicationduration of a load applied in the suction-attaching direction from theoutside from a period of time during which a voltage signal iscontinuously output. The application duration of a load is length of aperiod of time during which the suction-attachment detection unit 238has continuously detected the load.

In addition, the suction-attachment detection unit 238 may furtherdetect a load in the detaching direction applied from the outside. Inthis case, the suction-attachment detection unit 238 detects a tensileload applied from the outside as a load in the detaching direction. Notethat the suction-attachment detection unit 238 may further include atilt sensor configured to detect a direction of the load sensor andacquire an angle between the direction of the load sensor and thedetaching direction. In this case, the suction-attachment detection unit238 detects a length of a tensile load vector that is projected onto thedetaching direction as a load in the detaching direction. In such aconfiguration, even when the camera unit 11 and the control unit 23 aretilted, it is possible to detect a load in the detaching directionaccurately.

On this occasion, when a load in the detaching direction is applied fromthe outside, the suction-attachment detection unit 238 outputs a voltagesignal corresponding to the load in the detaching direction to the busline 241. Specifically, the suction-attachment detection unit 238, whendetecting a detectable load, outputs a voltage signal having a voltagevalue proportional to the magnitude of the detected load to thecontroller 231. While detecting a load, the suction-attachment detectionunit 238 continuously outputs a voltage signal. The controller 231 iscapable of, by converting a voltage signal from the suction-attachmentdetection unit 238 into a voltage value, obtaining the magnitude of aload applied in the detaching direction from the outside. In addition,the controller 231 is capable of obtaining application duration of aload applied in the detaching direction from the outside from a periodof time during which a voltage signal is continuously output.

The suction-attachment determination unit 237 determines whether or nota suction-attachment condition that is satisfied when thesuction-attachment unit 12 suction-attaches on the suction-attachmentsubject surface 9 is satisfied. For example, the suction-attachmentdetermination unit 237 converts a voltage signal that thesuction-attachment detection unit 238 has output into a physicalquantity, such as the magnitude of a load in the suction-attachingdirection. The suction-attachment determination unit 237 determineswhether or not the magnitude of the obtained physical quantity satisfiesthe suction-attachment condition. The suction-attachment determinationunit 237, when determining that the suction-attachment condition issatisfied, outputs a suction-attachment signal to the controller 231.

The controller 231 is, for example, a CPU and controls respectivecomponents constituting the camera unit 11 and the control unit 23directly or indirectly. For example, when the suction-attachmentdetermination unit 237 determines that the suction-attachment conditionis satisfied, the controller 231 controls the camera unit 11 to startgeneration of image data. That is, the controller 231, when acquiring asuction-attachment signal from the suction-attachment determination unit237, controls the camera unit 11 to start generation of image data.

The lens 111 of the camera unit 11 is an optical element configured toguide incident subject luminous flux to the imaging element 112. Thelens 111 may be constituted by a group of a plurality of optical lenses.The imaging element 112 is, for example, a CMOS image sensor. Theimaging element 112 adjusts charge accumulation time by means of anelectronic shutter in accordance with an exposure time per framespecified by the controller 231, performs photoelectric conversion, andoutputs pixel signals. The imaging element 112 hands over the pixelsignals to the AFE 113. The AFE 113 performs level adjustment on thepixel signals according to amplification gain instructed by thecontroller 231, analog/digital (A/D) converts the pixel signals intodigital data, and transmits the digital data to the control unit 23 asimage data. Note that the camera unit 11 may include a mechanicalshutter and an iris diaphragm. When the camera unit 11 includes amechanical shutter and an iris diaphragm, the controller 231 can, by usethereof, adjust the amount of light incident on the imaging element 112.

The image input IF 232 bears the function of an image data acquisitionunit configured to successively acquire image data captured by thecamera unit 11, that is, acquires image data from the camera unit 11connected to the control unit 23 and hands over the acquired image datato the bus line 241.

The work memory 233 is constituted by, for example, a volatile highspeed memory. The work memory 233 accepts image data from the AFE 113via the image input IF 232 and stores the accepted image data as oneframe of image data. The work memory 233 hands over image data to theimage processing unit 235 in units of frame. In addition, the workmemory 233 is also appropriately used as a temporary storage area whenthe image processing unit 235 is in the process of performing imageprocessing.

The image processing unit 235 performs various types of image processingon image data accepted from the work memory 233 and generates frameimages conforming to a predetermined format. For example, when videoimage data in the MPEG file format are generated, white balanceprocessing, gamma processing, and the like are performed on respectiveframes of image data and, subsequently, compression processing withineach frame of image data and compression processing among adjacentframes of image data are performed. The image processing unit 235successively generates frame images on which the respective processingis performed and hands over the generated frame images to the bus line241.

The movement determination unit 236 determines whether or not the cameraunit 11 has moved relatively to a surrounding environment. The movementdetermination unit 236, when determining that the camera unit 11 hasmoved, outputs a movement signal to the bus line 241.

For example, the movement determination unit 236 accepts successiveframe images from the image processing unit 235 and calculatesdifferences between a preceding frame image and its succeeding frameimage as movement vectors of the respective pixels. Next, a set ofpixels the movement vectors of which are zero is extracted as animmobile region. The immobile region is a region that is immobilerelatively to the camera unit 11.

Subsequently, the movement determination unit 236 generates binaryimages in each of which pixels in an immobile region have a value of “0”and pixels outside the immobile region have a value of “1”. Thegenerated binary images have noise removed by a known noise removalmethod, such as a morphological transformation. A region represented bypixels having a value of “1” in a binary image after noise removal isestimated to correspond to a region that is moving relatively to thecamera unit 11. Therefore, when the number of pixels having a value of“1” existing in a binary image after noise removal is equal to orgreater than a predetermined movement criterion value (for example, 50%of the total number of pixels), the movement determination unit 236 candetermine that the camera unit 11 is moving. Note that, in the example,specific numerical values of respective parameters used in the noiseremoval and the movement criterion value are determined depending on theresolution, precision, and the like of the camera unit 11 and can bedetermined through physical simulation or preliminary experiment.

The image output unit 239, when instructed by the controller 231,outputs image data accepted from the work memory 233 to the recordingunit 242. On this occasion, the image output unit 239 may convert frameimages accepted from the image processing unit 235 into image data againand output the image data to the recording unit 242.

The recording unit 242 is a device capable of recording output imagedata, and a nonvolatile memory, such as a flash memory, can be used asthe recording unit 140. Note that, although, in FIG. 7, an example inwhich the recording unit 242 is included in the image capturing device 2is illustrated, the recording unit 242 may be included in a terminalexternal to the image capturing device 2. In this case, the image outputunit 239 outputs image data to the external recording unit 242 by meansof wireless or wired communication via, for example, a communication IF(not illustrated) included in the control unit 23.

The brightness determination unit 240 determines brightness of frameimages accepted from the image processing unit 235. For example, thebrightness determination unit 240 extracts a value of the luminancesignal Y from YCbCr information of each pixel included in a frame imageand calculates an average value of the luminance values of therespective pixels as brightness of the frame image. The brightnessdetermination unit 240 outputs calculated brightness of frame images tothe controller 231. Note that the brightness determination unit 240 mayarbitrarily extract some pixels included in a frame image and calculatean average value of luminance values of the pixels as brightness of theframe image. In addition, the brightness determination unit 240 mayacquire RGB information of each pixel in place of YCbCr information and,using a generally known conversion formula, convert the RGB informationinto luminance information. On this occasion, the brightnessdetermination unit 240 may approximately calculate a luminance value ofeach pixel by converting only the G value of the RGB information. Inaddition, the brightness determination unit 240 may convert YCbCrinformation of each pixel included in a frame image into luminosityinformation and calculate an average value of luminosity values of therespective pixels as brightness of the frame image. Further, thebrightness determination unit 240 may extract a value of the luminancesignal Y from YCbCr information of each pixel included in image dataaccepted from the work memory 233 and calculate brightness of a frameimage.

The system memory 234 is constituted by a nonvolatile recording medium,such as a solid-state drive (SSD). The system memory 234 records andretains constants, variables, set values, control programs, and the likethat are necessary at the time of operation of the image capturingdevice 2. Control performed by the controller 231 is achieved by controlprograms and the like read from the system memory 234.

Next, a control flow of the image capturing device 2 will be described.FIG. 8 is a flow diagram illustrating the control flow of the imagecapturing device 2. The flow is started at a point of time at which thecontrol unit 23 becomes ready to operate. The point of time at which thecontrol unit 23 becomes ready to operate is, for example, a point oftime at which the user turns on the power supply of the image capturingdevice 2. In the present embodiment, an example of a case where a sensorconfigured to detect a load in the suction-attaching direction appliedfrom the outside is used as the suction-attachment detection unit 238will be described.

First, in step S110, the suction-attachment detection unit 238 detects aphysical quantity representing a relationship between thesuction-attachment unit 12 and the suction-attachment subject surface 9.Specifically, the suction-attachment detection unit 238 detects a loadin the suction-attaching direction applied from the outside. In thiscase, the suction-attachment detection unit 238 outputs a voltage signalcorresponding to the magnitude of the load in the suction-attachingdirection applied from the outside to the bus line 241. When unable todetect a load in the suction-attaching direction applied from theoutside, the suction-attachment detection unit 238 does not have tooutput a voltage signal to bus line 241. The suction-attachmentdetermination unit 237 converts the voltage signal accepted from thesuction-attachment detection unit 238 and thereby acquires the magnitudeof the load in the suction-attaching direction applied from the outsideand application duration of the load. Subsequently, the flow proceeds tostep S120.

When the flow proceeds to step S120, the suction-attachmentdetermination unit 237 determines whether or not a relationship betweenthe suction-attachment unit 12 and the suction-attachment subjectsurface 9 satisfies a suction-attachment condition. Thesuction-attachment condition is a condition that is satisfied when thesuction-attachment unit 12 suction-attaches on the suction-attachmentsubject surface 9. In the present embodiment, the suction-attachmentdetermination unit 237 determines whether or not a relationship betweenthe magnitude of the load in the suction-attaching direction detected bythe suction-attachment detection unit 238 and application duration ofthe load satisfies a predetermined suction-attaching load condition. Thesuction-attaching load condition is a condition that is satisfied when aload required for the suction-attachment unit 12 to suction-attach onthe suction-attachment subject surface 9 is applied from the outside.When a relationship between the magnitude of the load in thesuction-attaching direction and application duration of the loadsatisfies the suction-attaching load condition, the suction-attachmentdetermination unit 237 determines that the suction-attachment conditionis satisfied.

For example, it can be defined that, when a load the magnitude of whichis equal to or greater than a preset suction-attaching load value (forexample, 10 G) is applied in the suction-attaching direction for apreset suction-attaching duration (for example, 1 second), thesuction-attaching load condition is satisfied. Alternatively, it can bedefined that, when a load is applied in the suction-attaching directionin such a way that the product of the magnitude of the load andapplication duration of the load becomes equal to or greater than apreset suction-attaching impulse value (for example, 100 N□s), thesuction-attachment condition is satisfied. In the examples describedabove, specific numerical values of the suction-attaching load value,the suction-attaching duration, and the suction-attaching impulse valueare determined depending on the structure, physical properties, and thelike of the suction-attachment unit 12. For example, the numericalvalues can be determined through physical simulation or preliminaryexperiment.

When a relationship between the magnitude of the load in thesuction-attaching direction and application duration of the loadsatisfies the above-described suction-attachment condition (Yes in stepS120), the suction-attachment determination unit 237 outputs asuction-attachment signal to the bus line 241 and the flow proceeds tostep S130. On the other hand, when the relationship between themagnitude of the load in the suction-attaching direction and applicationduration of the load does not satisfy the above-describedsuction-attachment condition (No in step S120), the flow returns to stepS110.

When the flow proceeds to step S130, that is, when the controller 231acquires the suction-attachment signal, the controller 231 initiatesgeneration and the like of image data. Specifically, the controller 231makes the camera unit 11 operate and capture images of the surroundingenvironment and generate image data. In addition, the controller 231makes the image processing unit 235 perform various types if imageprocessing on the generated image data and generate a plurality of frameimages. Subsequently, the flow proceeds to step S140.

When the flow proceeds to step S140, the controller 231 acquiresbrightness of the frame images that the brightness determination unit240 has determined. The controller 231 determines whether or not thebrightness of the frame images satisfies a predetermined brightnesscriterion. The brightness criterion is a criterion that is satisfiedwhen the camera unit 11 receives light from the surrounding environment.In other words, the brightness criterion is not satisfied when thecamera unit 11 does not receive light from the surrounding environmentand thus cannot generate normal image data.

For example, when an average of luminance values of pixels included in aframe image is equal to or greater than a preset luminance criterionvalue (for example, 10), it is determined that the predeterminedbrightness criterion is satisfied. In the example, a specific numericalvalue of the luminance criterion value is determined depending onimage-capturing precision and the like of the camera unit 11. Forexample, a luminance value of a frame image when darkness is capturedcan be determined as the luminance criterion value.

When the brightness of the frame images satisfies the above-describedbrightness criterion (Yes in step S140), the flow proceeds to step S150.On the other hand, when the brightness of the frame images does notsatisfy the above-described brightness criterion (No in step S140), theflow proceeds to step S170 without outputting image data to therecording unit 242. Note that, when, after output of image data to therecording unit 242 is performed in step S160, which will be describedlater, the flow returns to step S140, the flow proceeds to step S170after the controller 231 stops output of image data to the recordingunit 242. In such a configuration, when no normal image data can begenerated because the optical path of the camera unit 11 is cut off,such as when the image capturing device 2 is mistakenly suction-attachedto a non-transparent object, it is possible to prevent output of imagedata from being started.

When the flow proceeds to step S150, the movement determination unit 236determines whether or not the camera unit 11 has moved relatively to thesurrounding environment. When the movement determination unit 236determines that the camera unit 11 has moved (Yes in step S150), themovement determination unit 236 outputs a movement signal to the busline 241 and the flow proceeds to step S160. In step S160 onward, outputof image data to the recording unit 242 is started. In such aconfiguration, no sooner is the image capturing device 2suction-attached on the suction-attachment subject surface 9 and doesthe camera unit 11 move than recording of image data can be started.

On the other hand, when the movement determination unit 236 determinesthat the camera unit 11 has not moved (No in step S150), the flowreturns to step S150 and the processing in the step is repeated. Notethat, when, after output of image data to the recording unit 242 isperformed in step S160, which will be described later, the flow returnsto step S150, the flow returns to step S150 after the controller 231stops output of image data to the recording unit 242 and the processingin the step is repeated. In such a configuration, no sooner is themovement of camera unit 11 stopped than the recording of image data canbe stopped.

When the flow proceeds to step S160, the controller 231 controls theimage output unit 239 to start output of image data to the recordingunit 242. Starting output of image data includes outputting image datato the outside of the image capturing device 2 by means of wireless orwired communication via a communication IF (not illustrated).Subsequently, the flow proceeds to step S170.

When the flow proceeds to step S170, the suction-attachment detectionunit 238 detects a load in the detaching direction applied from theoutside. The suction-attachment detection unit 238 outputs a voltagesignal corresponding to the magnitude of the load in the detachingdirection applied from the outside to the bus line 241. When unable todetect a load in the detaching direction applied from the outside, thesuction-attachment detection unit 238 does not have to output a voltagesignal to the bus line 241. The suction-attachment determination unit237 converts the accepted voltage signal and thereby acquiresinformation on the magnitude of the load in the detaching directionapplied from the outside and application duration of the load.Subsequently, the flow proceeds to step S180.

When the flow proceeds to step S180, the suction-attachmentdetermination unit 237 determines whether or not a relationship betweenthe suction-attachment unit 12 and the suction-attachment subjectsurface 9 satisfies a detachment condition. The detachment condition isa condition that is satisfied when the suction-attachment unit 12 isdetached from the suction-attachment subject surface 9. In the presentembodiment, the suction-attachment determination unit 237 determineswhether or not a relationship between the magnitude and applicationduration of the load in the detaching direction detected by thesuction-attachment detection unit 238 satisfies a predetermineddetaching load condition. The detaching load condition is a conditionthat is satisfied when a load required for the suction-attachment unit12 to be detached from the suction-attachment subject surface 9 isapplied from the outside. When a relationship between the magnitude andapplication duration of the load in the detaching direction detected bythe suction-attachment detection unit 238 satisfies the detaching loadcondition, the suction-attachment determination unit 237 determines thatthe detachment condition is satisfied.

For example, it can be defined that, when a load the magnitude of whichis equal to or greater than a preset detaching load value (for example,10 G) is applied in the detaching direction for a preset detachingduration (for example, 1 second), the detaching load condition issatisfied. Alternatively, it can be defined that, when a load is appliedin the detaching direction in such a way that the product of themagnitude of the load and application duration of the load becomes equalto or greater than a preset detaching impulse value (for example, 100N□s), the detaching load condition is satisfied. In the examplesdescribed above, specific numerical values of the detaching load value,the detaching duration, and the detaching impulse value are determinedwith the structure, physical properties, and the like of thesuction-attachment unit 12 taken into consideration. For example, thenumerical values can be determined through physical simulation orpreliminary experiment.

When a relationship between the magnitude of the load in the detachingdirection and application duration of the load satisfies theabove-described detachment condition (Yes in step S180), thesuction-attachment determination unit 237 outputs a detachment signal tothe bus line 241. The controller 231, when acquiring the detachmentsignal, stops the output of image data to the recording unit 242 andterminates the flow. On the other hand, when the relationship betweenthe magnitude of the load in the detaching direction and applicationduration of the load does not satisfy the above-described detachmentcondition (No in step S180), the flow returns to step S110. In such aconfiguration, since no sooner is the image capturing device 2 detachedfrom the suction-attachment subject surface 9 than the generation andthe like of image data are stopped, it is possible to stop output ofimage data promptly.

By repeating steps S110 to S180, which have been described thus far, theimage capturing device 2 is capable of promptly recording thesurrounding environment when the camera unit 11 has moved. It should benoted that the present disclosure is not limited to the above-describedembodiment and can be appropriately modified as long as the modificationdoes not deviate from the scope of the present embodiment.

(Variations)

In the above-described embodiment, a case where the suction-attachmentdetection unit 238 detects a load in the suction-attaching directionapplied from the outside was described. Hereinafter, as a variation ofthe embodiment, a case where the suction-attachment detection unit 238detects an air pressure on the inner side of the suction cup 121 will bedescribed.

In the variation, the suction-attachment detection unit 238 is, forexample, an air pressure sensor of a piezoresistive type and is arrangedon the inner side of the suction cup 121. The suction-attachmentdetection unit 238 detects an air pressure on the inner side of thesuction cup 121 and outputs a voltage signal corresponding to themagnitude of detected air pressure to the bus line 241 by means ofwireless or wired communication.

On this occasion, in step S110, the suction-attachment detection unit238 detects a pressure on the inner side of the suction cup 121. Whenthe suction cup 121 is suction-attached on the suction-attachmentsubject surface 9, the suction-attachment detection unit 238 detects apressure in the sealed space 91. The suction-attachment detection unit238 outputs a voltage signal corresponding to the pressure on the innerside of the suction cup 121 to the bus line 241. In step S110, when thepressure on the inner side of the suction cup 121 is equal to or greaterthan a preset pressure (for example, 9×10⁴ Pa), the suction-attachmentdetection unit 238 does not have to output a voltage signal to the busline 241. The suction-attachment determination unit 237 converts theaccepted voltage signal and thereby acquires the magnitude of thepressure on the inner side of the suction cup 121. Subsequently, theflow proceeds to step S120.

When the flow proceeds to step S120, the suction-attachmentdetermination unit 237 determines whether or not the pressure detectedby the suction-attachment detection unit 238 satisfies asuction-attaching pressure condition. In the present embodiment, thesuction-attaching pressure condition is a condition that is satisfiedwhen the pressure on the inner side of the suction cup 121 reaches apressure required for the suction-attachment unit 12 to suction-attachon the suction-attachment subject surface 9. When the pressure detectedby the suction-attachment detection unit 238 satisfies thesuction-attaching pressure condition, the suction-attachmentdetermination unit 237 determines that the suction-attachment conditionis satisfied.

For example, it can be defined that, when the pressure detected by thesuction-attachment detection unit 238 is equal to or less than a presetsuction-attaching pressure value (for example, 5×10⁴ Pa), thesuction-attaching pressure condition is satisfied. In the examplesdescribed above, a specific numerical value of the suction-attachingpressure value is determined depending on the structure, physicalproperties, and the like of the suction-attachment unit 12. For example,the numerical value can be determined through physical simulation orpreliminary experiment.

When the pressure detected by the suction-attachment detection unit 238satisfies the above-described suction-attachment condition (Yes in stepS120), the suction-attachment determination unit 237 outputs asuction-attachment signal to the bus line 241 and the flow proceeds tostep S130. On the other hand, when the pressure detected by thesuction-attachment detection unit 238 does not satisfy theabove-described suction-attachment condition (No in step S120), the flowreturns to step S110.

Since steps S130 to S160 in the variation are the same as those in theabove-described embodiment, descriptions thereof will be omitted.

In the variation, when the flow proceeds to step S170, thesuction-attachment detection unit 238 detects a pressure on the innerside of the suction cup 121. When the suction cup 121 issuction-attached on the suction-attachment subject surface 9, thesuction-attachment detection unit 238 detects a pressure in the sealedspace 91. The suction-attachment detection unit 238 outputs a voltagesignal corresponding to the magnitude of the pressure on the inner sideof the suction cup 121 to the bus line 241. The suction-attachmentdetermination unit 237 converts the accepted voltage signal intoinformation on voltage values and application duration and therebyacquires information on the magnitude of the pressure on the inner sideof the suction cup 121. Subsequently, the flow proceeds to step S180.

When the flow proceeds to step S180, the suction-attachmentdetermination unit 237 determines whether or not the pressure detectedby the suction-attachment detection unit 238 satisfies a predetermineddetaching pressure condition. The detaching pressure condition is acondition that is satisfied when the pressure on the inner side of thesuction cup 121 reaches a pressure causing the suction-attachment unit12 to be detached from the suction-attachment subject surface 9, thatis, a preset pressure. When the pressure detected by thesuction-attachment detection unit 238 satisfies the detaching pressurecondition, the suction-attachment determination unit 237 determines thatthe detachment condition is satisfied.

For example, it can be defined that, when the pressure detected by thesuction-attachment detection unit 238 in step S170 is equal to orgreater than a preset detaching pressure value (for example, 9×10⁴ Pa),the detaching pressure condition is satisfied. In the example, aspecific numerical value of the detaching pressure value is determineddepending on the structure, physical properties, and the like of thesuction-attachment unit 12. For example, the numerical value can bedetermined through physical simulation or preliminary experiment.

When the pressure detected by the suction-attachment detection unit 238in step S170 satisfies the above-described detaching pressure condition(Yes in step S180), the suction-attachment determination unit 237outputs a detachment signal to the bus line 241. The controller 231,when acquiring the detachment signal, stops the output of image data tothe recording unit 242 and terminates the flow. On the other hand, whenthe pressure detected by the suction-attachment detection unit 238 instep S170 does not satisfy the above-described detachment pressurecondition (No in step S180), the flow returns to step S110. Even in sucha configuration, since no sooner is the image capturing device 2detached from the suction-attachment subject surface 9 than thegeneration and the like of image data are stopped, it is possible tostop output of image data promptly.

By repeating steps S110 to S180, which have been described thus far, theimage capturing device 2 according to the above-described variation iscapable of promptly recording the surrounding environment when the imagecapturing device 2 including the camera unit 11 has moved.

In addition, although, in the above-described embodiment, in order todescribe an image capturing device according to the present disclosure,the description was made using as an example a device configured tocapture images of a surrounding environment on the outside through asuction-attachment subject surface, the image capturing device accordingto the present disclosure is not limited to the above-described example.That is, the image capturing device according to the present disclosuremay be a device configured to capture images of a surroundingenvironment in the opposite direction to the suction-attaching directionor the vertical direction. Even in such a device, by having aconfiguration equivalent to the camera unit 11 and the control unit 23described above and repeating processing in steps S110 to S180, theimage capturing device is capable of promptly recording a surroundingenvironment when the camera unit 11 has moved.

In addition, in the above-described embodiment, when, after it isdetermined that the pressure detected by the suction-attachmentdetection unit 238 in steps S110 to S180 does not satisfy theabove-described detaching pressure condition (No in step S180), theprocessing from step S110 onward is repeated again, the processing instep S120 in the second or later round may be appropriately omittedwithin an extent not impairing advantageous effects of the presentdisclosure. When, in the processing in the second or later round, thesuction-attachment condition in step S120 and the brightness conditionin step S140 are satisfied, omitting the processing in the steps anddetermining whether or not the camera unit 11 is moving in step S150enables the control flow to be simplified.

In addition, when the brightness determination unit 240 monitors changein the brightness even after, in step S140, it is determined that thebrightness criterion is satisfied and a sudden change in the brightnessoccurs due to entrance or exit into or from a tunnel while image dataare output, the output of image data does not have to be stopped.Further, when the brightness does not recover for a predetermined periodof time measured by the timer of the CPU, which will be described later,the output of image data may be stopped.

In addition, in the above-described embodiment, a configuration wasdescribed in which the controller 231 starts output of image data to therecording unit 242 when, after the suction-attachment determination unit237 determines that the suction-attachment condition is satisfied instep S120, the brightness determination unit 240 further determines thatthe brightness criterion is satisfied in step S140 and the movementdetermination unit 236 determines that the camera unit 11 is moving instep S150, resulting in all the conditions being determined to besatisfied.

However, the determination of whether or not the suction-attachmentcondition is satisfied, the determination of whether or not thebrightness criterion is satisfied, and the determination of whether ornot the camera unit 11 is moving do not have to be performed in thisorder. For example, even when the suction-attachment determination unit237 has not determined that the suction-attachment condition issatisfied, the movement determination unit 236 may first determinewhether or not the camera unit 11 is moving and, subsequently, thesuction-attachment determination unit 237 may determine that thesuction-attachment condition is satisfied. In this configuration, when,after the movement determination unit 236 has determined that the cameraunit 11 is moving or at the same time when the movement determinationunit 236 determines that the camera unit 11 is moving, thesuction-attachment determination unit 237 determines that the brightnesscriterion is satisfied and the suction-attachment condition issatisfied, the controller 231 may start output of image data to therecording unit 242.

In addition, in the above-described embodiment, the image capturingdevice 2 may further include an acceleration sensor configured toacquire an acceleration of the camera unit 11. The acceleration sensoris, for example, a capacitance detection type acceleration sensor. Inthis case, the acceleration sensor outputs an electric signalcorresponding to the detected acceleration to the movement determinationunit 236. The movement determination unit 236 converts the electricsignal acquired from the acceleration sensor into information ofacceleration. The movement determination unit 236 integrates theacquired acceleration and thereby calculates a speed of the camera unit11 and, when the speed is equal to or greater than a predetermined speedcriterion value, determines that the camera unit 11 has moved. In thiscase, the movement determination unit 236 is not required to performimage processing as described in the above-described embodiment. Inaddition, in this case, even when the surrounding environment and thecamera unit are moving at the same speed, the movement determinationunit 236 can detect that the camera unit 11 is moving. Note that, thespeed criterion value in the example is determined depending onprecision and the like of the acceleration sensor and can be determinedthrough physical simulation or preliminary experiment.

In addition, in the above-described embodiment, the image capturingdevice 2 may further include a signal acquisition unit configured toacquire an external signal relating to information on speed and aposition. The external signal is, for example, a GPS signal or a signalthat can be obtained through an on-vehicle network, such as a controllerarea network (CAN). In this case, the movement determination unit 236converts the external signal acquired by the signal acquisition unitinto speed information of the image capturing device 2 and, when thespeed of the image capturing device 2 is equal to or greater than apredetermined speed criterion value, determines that the camera unit hasmoved. In this case, the movement determination unit 236 is also notrequired to perform image processing as described in the above-describedembodiment.

In addition, although, in the above-described embodiment, a case wherethe controller 231 of the image capturing device 2 makes the camera unitoperate when determining that the suction-attachment condition issatisfied was described, the camera unit 11 may be configured toconstantly operate. Alternatively, the camera unit 11 may startoperation through a start-up operation by the user.

Note that, in the above-described embodiment, it is preferable toinclude a condition requiring application duration of a load to be equalto or longer than a preset suction-attaching duration in thesuction-attaching load condition. Such a configuration enables the imagecapturing device 2 to be prevented from malfunctioning when a load inthe suction-attaching direction is instantaneously applied, such as whenthe image capturing device 2 hits some object.

In addition, in the above-described embodiment, it is preferable toinclude a condition requiring application duration of a load to be equalto or longer than a preset detaching duration in the detaching loadcondition. Such a configuration enables the image capturing device 2 tobe prevented from malfunctioning when a load in the detaching directionis instantaneously applied, such as when the image capturing device 2hits some object.

In addition, although, in the above-described embodiment, a case where aload in the suction-attaching direction applied to the image capturingdevice 2 from the outside is detected and an example in which thesuction-attachment detection unit 238 detects pressure on the inner sideof the suction cup were described, the physical quantity that thesuction-attachment detection unit detects is not limited to theexamples. The suction-attachment detection unit 238 may be a detectionunit that detects a physical quantity other than a load in thesuction-attaching direction and pressure as long as detecting a physicalquantity representing a relationship between the suction-attachment unit12 and the suction-attachment subject surface 9.

For example, the suction-attachment detection unit 238 may be a distancesensor configured to detect a distance between the camera unit 11 andthe suction-attachment subject surface 9. On this occasion, thesuction-attachment detection unit 238 outputs a distance signalcorresponding to the detected distance to the bus line. Thesuction-attachment determination unit 237 converts the distance signalaccepted from the suction-attachment detection unit 238 and therebyacquires the distance that the suction-attachment detection unit 238detected. When the distance is equal to or less than a presetsuction-attaching distance (for example, 1 cm), the suction-attachmentdetermination unit 237 can determine that the suction-attachmentcondition is satisfied. Note that a specific numerical value of thesuction-attaching distance is determined with the position of thesuction-attachment detection unit and the structure, physicalproperties, and the like of the suction-attachment unit taken intoconsideration and can be determined through physical simulation orpreliminary experiment.

In addition, in the example, when the distance is equal to or greaterthan a preset detaching distance (for example, 5 cm), thesuction-attachment determination unit 237 can determine that thedetachment condition is satisfied. Note that a specific numerical valueof the detaching distance is determined with the position of thesuction-attachment detection unit 238 and the structure, physicalproperties, and the like of the suction-attachment unit 12 taken intoconsideration and can be determined through physical simulation orpreliminary experiment.

The embodiments and their variations described above can be embodiedindependently or in an appropriate combination thereof. The plurality ofembodiments and variations have novel features that differ from oneanother. Therefore, the plurality of embodiments and variationscontribute to achieving objects or solving problems that differ from oneanother and contribute to attaining advantageous effects that differfrom one another.

In addition, in the above-described embodiments, the respectivecomponents described in the drawings as functional blocks performingvarious processing can be constituted by a CPU, a memory, and othercircuits in the hardware aspect and are achieved by programs and thelike loaded on the memory in the software aspect. Therefore, it isunderstandable for a person skilled in the art that the functionalblocks can be achieved in various manners, such as by only hardware, byonly software, and by a combination thereof, and the achievement manneris not limited to any manner.

A (The) program can be stored and provided to a computer using any typeof non-transitory computer readable media. Non-transitory computerreadable media include any type of tangible storage media. Examples ofnon-transitory computer readable media include magnetic storage media(such as floppy disks, magnetic tapes, hard disk drives, etc.), opticalmagnetic storage media (e.g. magneto-optical disks), CD-ROM (compactdisc read only memory), CD-R (compact disc recordable), CD-R/W (compactdisc rewritable), and semiconductor memories (such as mask ROM, PROM(programmable ROM), EPROM (erasable PROM), flash ROM, RAM (random accessmemory), etc.). The program may be provided to a computer using any typeof transitory computer readable media. Examples of transitory computerreadable media include electric signals, optical signals, andelectromagnetic waves. Transitory computer readable media can providethe program to a computer via a wired communication line (e.g. electricwires, and optical fibers) or a wireless communication line.

The first and second embodiments can be combined as desirable by one ofordinary skill in the art.

Further, the scope of the claims is not limited by the embodimentsdescribed above.

Furthermore, it is noted that, Applicant's intent is to encompassequivalents of all claim elements, even if amended later duringprosecution.

What is claimed is:
 1. An image capturing device comprising: a cameraconfigured to capture images of a surrounding environment and generateimage data; a suction-attachment unit comprising a suction cup and ahousing, the housing configured to support the camera and the suctioncup configured to be fixed on a suction-attachment subject surface by auser; at least one memory configured to store a program; and at leastone central processing unit (CPU) communicatively coupled to the camera,suction-attachment unit, and the memory, the CPU configured to executethe program stored in the memory to: determine whether or not the imagedata can be output to a recording unit; and control output of the imagedata to the recording unit, based on the determination whether or notthe image data can be output to the recording unit, wherein thedetermination whether or not the image data can be output to therecording unit comprises: determining whether or not brightness of aframe image generated based on the image data satisfies a brightnesscriterion; and determining whether or not a relationship between thesuction cup and the suction-attachment subject surface satisfies apredetermined suction-attachment condition.
 2. The image capturingdevice according to claim 1, wherein the determination whether or notthe image data can be output to the recording unit includes: determiningwhether or not the camera has moved.
 3. The image capturing deviceaccording to claim 2, wherein the at least one CPU is further configuredto start output of the image data to the recording unit when thesuction-attachment condition is satisfied, the brightness criterion issatisfied, and the camera has moved.
 4. The image capturing deviceaccording to claim 2, wherein the at least one CPU is further configuredto stop output of the image data to the recording unit when the cameradoes not move.
 5. The image capturing device according to claim 2,wherein the at least one CPU is further configured to detect a physicalquantity representing a relationship between the suction cup and thesuction-attachment subject surface, wherein the suction cup is fixed onthe suction-attachment subject surface by being pressed in asuction-attaching direction from an outside, the at least on CPU isconfigured to: detect a load in the suction-attaching direction appliedfrom the outside, and determine that the suction-attachment condition issatisfied when a relationship between a magnitude and applicationduration of a load in the suction-attaching direction detected by the atleast one CPU satisfies a predetermined suction-attaching loadcondition.
 6. The image capturing device according to claim 2, whereinthe at least one CPU is further configured to detect a physical quantityrepresenting a relationship between the suction cup and thesuction-attachment subject surface, wherein the suction cup is fixed onthe suction-attachment subject surface by a decompressed sealed spacebeing formed between the suction cup and the suction-attachment subjectsurface, the at least one CPU is configured to: detect a pressure in thesealed space, and determine that the suction-attachment condition issatisfied when pressure detected by the at least one CPU satisfies apredetermined suction-attaching pressure condition.
 7. The imagecapturing device according to claim 2, wherein the at least one CPU isfurther configured to: determine whether or not a relationship betweenthe suction cup and the suction-attachment subject surface satisfies apredetermined detachment condition, and stop output of the image data tothe recording unit when the at least one CPU determines that thedetachment condition is satisfied.
 8. The image capturing deviceaccording to claim 5, wherein the at least one CPU is configured to: notstart output of the image data to the recording unit when the brightnessof the frame image does not satisfy a predetermined brightnesscriterion, even when a relationship between a magnitude and applicationduration of a load in the suction-attaching direction detected by the atleast one CPU satisfies a start condition.
 9. An image capturing devicecomprising: a camera configured to capture images of a surroundingenvironment and generate image data; a suction-attachment unitcomprising a suction cup and a housing, the housing configured tosupport the camera and the suction cup configured to be fixed on asuction-attachment subject surface by a user; at least one memoryconfigured to store a program; and at least one central processing unit(CPU) communicatively coupled to the camera, suction-attachment unit,and the memory, the CPU configured to execute the program stored in thememory to: determine whether or not the image data can be output to arecording unit; control output of the image data to the recording unit,based on a determination result by the determination unit; and detect aload in a detaching direction applied from an outside, wherein the atleast one CPU is configured to output of the image data to the recordingunit when a relationship between a magnitude and application duration ofa load in the detaching direction detected by the at least one CPUsatisfies a predetermined stop condition.
 10. An image capturing methodcomprising: a step of, after a camera is fixed on a suction-attachmentsubject surface by using a suction cup, capturing images of asurrounding environment with the camera and generating image data; astep of determining whether or not the image data can be output to arecording unit; and a step of controlling output of the image data tothe recording unit, based on a determination result, wherein the step ofdetermining includes: determining whether or not brightness of a frameimage generated based on the image data satisfies a brightnesscriterion; and determining whether or not a relationship between thesuction-attachment unit and the suction-attachment subject surfacesatisfies a predetermined suction-attachment condition.